Cable Management, One Step at a Time
Global automation supplier, Comau Inc. in Southfield, Michigan, takes a modular approach to cable management.
“We generally break the cable up into different sections,” says Mark Anderson, Technical Development Manager at Comau. “We’ll have one section of high-flex cable going from joint 6 down to joint 1. Then we’ll have a low-flex cable from the base of the robot back to our cabinet. If the robot were to be mounted on some type of 7th-axis Screenshot from 3D vision guidance software using a 2D camera to guide a robot in six degrees of freedom to locate specific features on an automotive body side (Courtesy of Comau Inc.)slide, we would have another high-flex cable that would go through the 7th-axis CAT track and then a low-flex cable from the end of the CAT track back to our cabinet.”
“That way if there’s a failure in one area, you can replace just that section. It’s much quicker,” says Anderson. “For instance, the cable area along the robot is going to see more bending, flexing and twisting. It takes less time to repair that section rather than replace the entire expanse.”
“The low-flex cable is also lower cost, so you don’t have to replace a very long, expensive cable,” he adds.
Even though Comau manufactures its own robots, the company considers itself “a solutions provider” rather than a product provider. This dictates how they approach every aspect of an application and drives innovation. Comau serves the automotive and aerospace industries, among others.
“We review every application with an open mind, independently and objectively,” says Anderson. “We document the requirements for each individual process, such as desired accuracy, expected product variation, system model flexibility whether they’re running one model, two models, or more and the difference between those models, and any specific customer requirements.”
Anderson says by the time they go through this process, it’s usually determined whether a vision guided application is robot or fixed mounted.
“A lot of our customers would rather us mount the camera on an end effector and have a more flexible system. The body shops where we install systems are traditionally designed to accept a very large and wide product variation.” He says these variants can range from sedans to SUVs.
VGR in Six Degrees of Freedom
“The value of our system is that we offer a very flexible vision guided system that provides a six-degree-of-freedom offset to the robot without requiring any calibration,” explains Anderson, who helped Comau develop robot vision guidance technology for drilling holes in the inlet ducts of F-35 fighter jets. “Our RecogniSense® system is very simple to set up.”
“We helped develop the system out of necessity to fill a void in the VGR arena. We’re an integrator at heart. We want to make sure we provide the right tool for our customer.”
“Vision is not a one-size-fits-all tool,” he says. “Every vision system has its own pros and cons. We probably use just as many Cognex systems as we do RecogniSense.”
Anderson says that in addition to the simple setup and not needing calibration, the patent-pending system has a wide area of view with a minimal number of cables and cords. He says they basically have one cord that plugs into the camera.
“We use a process called visual servoing,” explains Anderson. “It’s an iterative process in which you stop, take a picture, make an adjustment, and then take a picture again. Through that iterative process, we drive the robot to the proper position.”
“We’re able to use this visual servoing process and still achieve a very fast cycle time. Image processing happens in a couple hundred milliseconds.”
This video courtesy of Comau shows the RecogniSense technology being used for automotive wheelhouse hemming. This video shows in more detail how the technology works.
Anderson says that the RecogniSense camera is not always robot mounted. Comau uses it in fixed-mount applications for laser brazing. In these cases, visual servoing isn’t necessary because the image acquisition Human-like dexterity and internal cables help this dual-arm robot perform precise tasks in tight spaces required in laboratory automation (Courtesy of Yaskawa Motoman)and processing occur in the background.